This calculator is for monthly or yearly regular investments of a set amount (with no withdrawals). It finds the amount you will have at the end of your investment.
It assumes that the investments are made at the beginning of the month (or year). The formula that typically appears in Algebra books are for investments made at the end of the month.

This material is based upon work supported by the
National Science Foundation under Grant DUE-0226284.
Any opinions, findings, and conclusions or recommendations
expressed in this material are those of the author(s)
and do not necessarily reflect the views of the
National Science Foundation.